Described herein is a process and a composition for the fabrication of an electronic device. More specifically, described herein are compositions for forming a silicon-containing film in a plasma enhanced atomic layer deposition (PEALD) process. Exemplary silicon-containing films that can be deposited using the compositions and methods described herein include, without limitation, stoichiometric or non-stoichiometric, silicon nitride, silicon carbonitride, silicon oxynitride, silicon aluminum nitride, silicon oxide, and silicon carboxide films.
Silicon nitride is often used as an insulator and chemical barrier in manufacturing integrated circuits, to electrically isolate different structures or as an etch mask in bulk micromachining. As a passivation layer for microchips, it is superior to silicon dioxide, as it is a significantly better diffusion barrier against water molecules and sodium ions, two major sources of corrosion and instability in microelectronics. It is also used as a dielectric between polysilicon layers in capacitors in analog chips.
One of the commercial methods for forming silicon nitride or films employs dichlorosilane and ammonia as the precursor reactants. Low pressure chemical vapor deposition (LPCVD) using precursors such as dichlorosilane and ammonia require high deposition temperatures to get the best film properties. For example, temperatures greater than 750° C. may be required to obtain reasonable growth rates and uniformities. Other processing issues involve the hazardous aspects of chlorine and chlorine byproducts.
Many of the newer semiconductor devices require silicon nitride films that have low etch rates, high film stresses, or both. It is also preferred, and sometimes necessary, that the films be formed at temperatures below 600° C. while maintaining good electrical characteristics. Film hardness is yet another factor to consider in the design of the electrical components and the silicon nitride films do offer extremely hard films.
The deposition of conformal, stoichiometric and non-stoichiometric silicon nitride films at low temperature, e.g., temperatures of about 500° C. or less or about 400° C. or less, which meet one or more criteria to be considered a high quality film, has been a long-standing industry challenge. There are several applications in semiconductor field such as advanced patterning or spacer which require high quality films. A silicon nitride film is considered a “high quality” film if it has one or more of the following characteristics: a density of 2.0 grams per cubic centimeter (g/cc) or greater, a low wet etch rate (as measured in dilute hydrofluoric acid (HF)), and combinations thereof compared to other silicon nitride films. In these or other embodiments, the refractive index for the silicon nitride film should be 1.8 or greater.
Accordingly, there is a need in the art to provide a low temperature (e.g., processing temperature of about 500° C. or less) method for depositing a conformal, high quality, silicon nitride film wherein the film has one or more of the following characteristics: a reflective index of 1.8 or higher, a density of 2.0 grams per cubic centimeter (g/cc) or greater, a low wet etch rate (as measured in dilute hydrofluoric acid (HF)), and combinations thereof compared to other silicon nitride films using other deposition methods or precursors.